For any kind of planning like you propose, it is essential to build in the following stages into your work: presentation, body and conclusion. You need to consider how you are going to introduce the topic and teach the basic concepts. Then, you need to think of what the main aspects are that you want your students to learn and what project or tasks you want them to complete where they practically apply their knowledge. Lastly, you need to consider how to finish off this topic approach and how you will assess their learning.
You might find it helpful to actually make a list of specific learning objectives that you want your students to learn. This will help you identify what content you need and also get you thinking about how you can assess those learning objectives, both in a continuous fashion and in a summative form (for example, an exam) at the end of this unit.